Mysql optimizing – querys with no indexes

Mysql optimization of a site is one of the most important aspects of optimizing a website.

If you have a website is very important to try to optimize it better. Optimizing a site you can get rid of a greater expense to a hosting service.

The first thing i try is to  add in my.conf (config mysql) the following code:

log-queries-not-using-indexes

What is the setting above? Simply addes the mysql query logs of  a sites that  do not use an index.

In other words: to find a result in a mysql table each record’s is compared with the condition of the query.

So if you have a query that finds data into a tabl;e with 100,000 records you will notice that during the process that  mysql resources used are extremely large compared to the situation that your query has a good index. But if I can not access the file my.conf? Nothing more simple …

Natural the question that comes now is: How do I know if a query correctly selects an index?

For this there EXPLAIN the syntax of MySQL. This is the syntax for explain query:

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Explain SELECT id, username FROM users WHERE id = 3

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The result of this query is a table with several fields that will contain two known possible_key and key.

These two fields actually shows you potential index and the index that MySQL’s chosen to use.

Soon I want to make available a mysql class that can help you easily debuggul and that contain data from this short tutorial. Soon other details …

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